The expansion of the agricultural activities in the world has brought about not only soil destruction in the large scale but also the grave influences on the environment. But the agriculture, in the original sense, has been developed in harmony with the natural ecosystems in loci. This Project focused on analyzing the rational management technology of paddy fields in the traditional agriculture in Indonesia from the viewpoints of sustainability and soil fertility. Mina padi system in Indonesia is an example, where fishes are reised in the paddy fields. We payd special attentions to mina padi from the viewpoints of,1) productivity of rice, upland crops and fishes in the field,2) the cycles of C and N in the field and home garden of the farmer,3) weed and pest controls,4) economic merits,We conducted the questionnaire survey, and the field experiment to make clear the rationality behind the mina padi systems from the viewpoint of economics and soil fertility.As the main biomass and N poo
… Morels, ricse plants, weeds in paddy fields, and vegitables fruit trees and livestock in home gardens were pointed out. Weeds for livestock feed and manure from livestock were the main flows connecting fields with home gardens. Thus, many pools and flows among versatile pools were known to exist in the agricultural ecosystem in Indonesia. Agricultural production in study villages was not only sold to the market but also used for family consumption, resulting in the decrease in expense. Although fish culture in paddy field increased the income from its production, it decreased the rice yield a little in the study village. Fish culture (for 4 years) did not increase soil fertility estimated from nitrogen mineralization and the total nitrogen content. In conclusion, the contribution of mina padi system in Indonesia to sustainable agriculture was estimated to be through the increase in family income rather than the soil fertility/yield increase.3)Jatisarono村では主たる農業所得を水稲栽培に依存(全農業収入の60%)し、水田養魚による所得は全農業所得の10%と少ないこと、Jatisarono村では市場へ出荷する量以上の量の魚を自家消費に回していること、4)水田養魚を行っている農家の水稲収量はそうでない農家の収量より低いこと、が判明した。以上の結果より、ジョグジャカルタ近郊の農業はそれ自体有機物・窒素循環の視点からは極めて多様なプールとフローを維持している伝統的で持続的な農業であり、農耕地で生産されるあらゆる光合成産物(一次生産物)を有効に利用した農業を実施していること、その際水田圃場と農家の裏庭との間で極めて太いフローのパイプを、家畜の飼料としての稲ワラ・モミ殻・水田雑草(水田圃場から裏庭)と厩肥(裏庭から水田圃場)を通して確立していることが判明した。しかし、インドネシアの伝統的農業に1つである水田養魚の「持続的農業」としての意義を評価したところ、水田養魚による土壌の肥沃性増進への寄与は予想に反して僅かであり、その主たる意義は所得の増大を通した農家経済の安定への寄与にあると結論された。 Less